feature: ilo run / check / build CLI verbs (0.12.0)

[danieljohnmorris]

Summary

Adds ilo run, ilo check, and ilo build as verb-noun subcommands matching cargo / go / zero toolchain conventions, while preserving every existing positional form for backwards compatibility. Ships in 0.12.0 alongside the modular skills work as a coherent CLI refresh.

• ilo run <file> [args] — exact alias for the bare positional ilo <file>; same dispatch, same engine selection, same arg handling
• ilo build <file> -o <out> [func] — alias for ilo compile
• ilo check <file> [--json] — new capability: lex + parse + import-resolve + verify, exit 0 if clean, exit 1 with diagnostics on stderr if not; does not execute the program. Useful for editor save-hooks, agent inner loops, CI gates that want type-only feedback. On a syntactically-broken input it still reports the parse error rather than crashing.

ilo run / ilo check / ilo build with no source argument now print a friendly Usage: ilo <verb> <file> line to stderr and exit 1, replacing the previous parser blowup (ILO-P020 incomplete function header for run from lexing the verb as inline ilo source). One of the manifesto wins of this PR: every agent who reached for the natural toolchain shape used to burn a retry decoding that error.

Repro before/after

$ ilo run                                        # before
{"code":"ILO-P020","message":"incomplete function header for `run`: ...

$ ilo run                                        # after
Usage: ilo run <file.ilo> [func] [args...]
       ilo run <inline-code> [func] [args...]

$ ilo check file.ilo --json                      # new
{"code":"ILO-T008","labels":[],"message":"return type mismatch: expected n, got _"...}

What's in the diff

• commit 1 (cli) — src/cli/args.rs adds Cmd::Build(CompileArgs) and Cmd::Check(CheckArgs); src/main.rs dispatches both (build forwards to compile_cmd, check calls the new check_cmd) and pre-clap-intercepts ilo run|check|build with no source for the friendly usage message
• commit 2 (tests) — 16 integration tests in tests/cli_verbs.rs: file / inline / args coverage for run, clean / type-error / parse-error / --json / no-args coverage for check, file + no-args coverage for build, plus 4 backwards-compat regression tests that the bare positional forms (ilo file.ilo, ilo file.ilo arg, ilo file.ilo func, ilo compile file.ilo -o out) all still work post-refactor
• commit 3 (docs) — SPEC.md CLI invocation section picks up the three new verb forms and explains the ilo check semantics; ai.txt and skills/ilo/SKILL.md regenerate from SPEC.md via build.rs; README.md Quick start picks up a verb-form example block

Site repo: docs/reference/cli.md updated separately and pushed to ilo-lang/site main as commit be8a82b.

Test plan

• cargo build --release clean
• cargo fmt --check clean
• cargo clippy --release --all-targets -- -D warnings clean
• 16/16 new tests in tests/cli_verbs.rs pass
• Full cargo test --release --features cranelift suite: 3179+ passing tests; one flaky vm::tests::vm_rdl_basic (TOCTOU on /tmp/ilo_vm_rdl_test.txt when run alongside vm_rdl_not_found) — passes in isolation, unrelated to this PR; pre-existing regression_inline_lambda failures on main caused by the recent --run-cranelift → --jit rename, also unrelated
• Smoke-tested every acceptance criterion in the brief by hand

Follow-ups

• The pre-existing regression_inline_lambda failures from the --run-cranelift → --jit rename should be cleaned up in a follow-up; out of scope here.
• A future PR can promote --bench to a full ilo bench subcommand and split --explain overload into ilo explain <code> per the brief's deferred-decisions section.

[codecov]

Codecov Report

❌ Patch coverage is 86.59794% with 13 lines in your changes missing coverage. Please review.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/main.rs	86.59%	13 Missing ⚠️

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